During the past 3.5 billion years,
99.5% of the carbon in CO2
had been sequestered
in carbonaceous rocks,
and to a much lesser extent,
in underground fossil fuels.
Current CO2 levels are very low
relative to billions of years ago.
140 million years ago,
the atmosphere had
2,500 parts per million (ppm)
of CO2.
About 18,000 years ago,
at the last peak glaciation,
CO2 was only 180 ppm,
down 92.8%.
At 180 ppm CO2,
the growth of
many plant species
was stunted.
The reduction of CO2 in the air
over the past 140 million years,
from 2,500 ppm to 180 ppm,
was from CaCO3
(calcium carbonate)
deposition from plankton
and coral reefs
in marine sediments.
During the major glaciations,
the cooling oceans
temporarily absorbed
some additional CO2
... but there was
outgassing of CO2
from the oceans
as they warmed
when the glaciers
were melting.
Human CO2 emissions
raised the CO2 level
to just over 400 ppm today.
The CO2 increase
during the Industrial Age
was mainly due to
fossil fuel combustion,
land-use change,
and cement production.
Note:
Both sets of ice core data
from Antarctica
show that changes in temperature
PRECEDE changes in CO2 levels,
suggesting that temperature change
is the CAUSE of the change
in the level of CO2.
The increase in CO2
in the atmosphere
is responsible for
increased plant growth.
There are thousands
of real science experiments
to prove that:
https://www.heartland.org/_template-assets/documents/CCR/CCR-IIb/Summary-for-Policymakers.pdf
https://www.heartland.org/_template-assets/documents/CCR/CCR-IIb/Summary-for-Policymakers.pdf
In higher CO2 environments,
plants become more efficient
at photosynthesis, growing faster
without using more water.
Greenhouse operators worldwide
inject additional CO2
into their greenhouses
to increase the growth
of their crops.
The optimum level of CO2
for plant growth
is between 800 ppm and 3,000 ppm,
much higher than the 400 ppm
in the global atmosphere today.
Many studies suggest
that 25% to 50%
of human-caused CO2 emissions
are absorbed by plants,
increasing plant biomass.
I call this a “greening of the Earth”.
CO2 has been higher than today
during most of the history
of life on Earth.
Every species on Earth
descended from ancestors
that thrived in much higher
CO2 levels than today.
There is no scientific proof
that increased CO2
will result in a disaster,
or even a minor problem !
CO2 is essential for all life on Earth.
Before humans began to burn fossil fuels,
the atmospheric concentration of CO2
was in a dangerous decline.
The optimum CO2 level
for plant growth
is at least 800 ppm,
and CO2 has been
above that level
for most of
the history of life
on our planet.
It makes no sense to call for
a reduction in the level of CO2,
because there is no evidence
that CO2 causes
catastrophic climate change.
Humans have
inadvertently disrupted
inadvertently disrupted
the gradual depletion of CO2
from the atmosphere,
that would have eventually
fallen to under 150 ppm,
a starvation level
for food crop plants.
Life on Earth depends on
those food crop plants.
We should not be worried
about today's CO2 levels,
of about 400 ppm,
climbing higher.
We should celebrate
CO2 levels increasing,
and the 'greening'
of our planet.